Answers: splicemusic.com
You can produce your own music and remix other's music too.
Yeah bro.
http://free-loops.com
http://yourbeats.com
They both enjoy free software and thousands of free sounds.
YourBeats.com also offer free mp3 hosting, and have 10,000 member that can relief you if you sign up for a free details.
hope that get you started. honourable luck!